Paul's supporters won control of state GOP conventions in Maine and Nevada last weekend, stripping Romney of delegates in Maine but graciously letting him keep the ones he won in Nevada's February caucuses. Next up: Republican state conventions in Minnesota, Missouri, Louisiana and Iowa.

"I don't think they'll be able to ignore us completely," said Kevin Erickson, a pastor from northeastern Minnesota who rescheduled a surgery to qualify as a national convention delegate for Paul.

The father of five supports his family on a single income but said he's budgeted about $6,000 to attend the GOP's August convention in Tampa, Fla. A lifelong Republican, Erickson said he's working hard for a platform that denounces what he sees as a weakening of due process when it comes to detentions authorized by the USA Patriot Act. He expects to have plenty of company.

Paul won't threaten Romney's hold on the GOP nomination -- Romney's delegate lead is so big he is likely to reach the 1,144 delegates he needs to clinch the nomination by the end of the month. The former Massachusetts governor is already in general election mode, focusing his energy on uniting the GOP and defeating President Barack Obama in November.

But Paul could have enough supporters in Tampa to cause trouble if they don't get what they want. And what do they want?

At the very least, they want a prominent speaking role for Paul at the convention, said Marianne Stebbins, who has coordinated Paul efforts in Minnesota. More broadly, they want a platform for their message of limited government as they work to reshape the Republican Party, one state at a time.

"I hope they're smart," Stebbins said of the Romney campaign. "Those margins, Romney versus Obama, are so thin that I hope they don't shove an entire constituency out of the party that they will need in November."

The Romney campaign treads lightly around Paul, careful not to offend his supporters but insistent that Romney is the nominee.

"Gov. Romney has a lot of respect for Dr. Paul and the energy his supporters bring to the process," Romney campaign spokeswoman Andrea Saul said in an email. "We look forward to working together to help Mitt Romney defeat President Obama this fall. As for individual state conventions, make no mistake that the Tampa convention will nominate Mitt Romney, and it will be his convention."

Romney has 856 delegates -- 288 shy of the number he needs to clinch the nomination. Paul, a Texas congressman, has 94, according to an Associated Press count.

There are 107 delegates at stake in primaries Tuesday in North Carolina, Indiana and West Virginia.

Primaries have not been Paul's strong suit -- he hasn't won a single primary or caucus. But Paul's supporters have successfully navigated the convention process in a number of states, adding to Paul's delegate total while gaining influence over state parties.

In Iowa and Nevada, Paul supporters were elected to lead their state Republican parties. In Maine, two Paul supporters were elected to the Republican National Committee. In Massachusetts, Paul's supporters denied a delegate spot to Kerry Healey, Romney's former lieutenant governor, even though Romney won the state's presidential primary with 72 percent of the vote, according to The Boston Globe.

"I've urged people to take the `over' in terms of how many delegates they think Paul will have at the convention," said Josh Putnam, an assistant political science professor at Davidson University who writes the political blog Frontloading HQ.

Paul's supporters are likely to make similar inroads in Minnesota, which holds its state GOP convention May 18-19. Paul has already dominated the state's congressional district conventions, winning at least 18 of the 24 national delegates selected, even though he finished a distant second to Rick Santorum in local caucuses in February.

"Republican Party activists with Paul leanings are affirming the campaign's delegate-win strategy and making lasting inroads into the party infrastructure, broadening the Republican footprint and strengthening the GOP base that suffers from a dearth of enthusiasm," Paul's national campaign manager, John Tate, said in a statement.

Many of Paul's libertarian views dovetail nicely with mainstream Republican ideas on limited government and low taxes. But Paul breaks with much of his party when he rails against American intervention abroad and government efforts to fight terrorism at home.

Paul will probably get a speaking slot at the convention but his influence over the party platform and power will be limited, said Rich Galen, a GOP strategist and former Newt Gingrich aide who is neutral in the 2012 race.

"If Ron Paul gets more delegates than Newt Gingrich, then he gets at least as good of a prime-time slot to speak at the convention," Galen said. But, he added, "Ron Paul's not going to be vice president, and he's not going to get a plank in the platform that Romney doesn't want."